18X8 40MM 235/45R18 2003 Sedan

I've spent way too much time researching this stuff this week especially since you get 70% BS answers when you use the search function. All my calculations and research says this setup sould be entirely fine for my 2003 sedan. I considered 245/45R18s, but they're a little too tall (26.8") and the Tire Rack says 225/45R18 which I think it way too short (25.9") and narrow for the 3,400lb sedan. The 235/45 matches the OEM height (26.3") perfectly though tire selection is somewhat limited for summer rubber.

 

I'd go either 245/40 or 245/45 for larger selection of tires. Your choice is really to go under or over OEM diameter. It doesn't matter which you choose as long as the front and rear diameters are within 3% of each, in this case your not going staggered, so it doesn't matter.

Also the OEM 235/45/18 setup is on a 7.5" wide rim, putting that on a 8" rim is going to stretch it a tiny bit, which is going to make the overall diameter smaller than the OEM setup.

 

Dave, they should fit fine.
Here is a pic of inTgr8r's 04 Sedan he had.
He was running 8.5" x 18" rims with a 42mm offset all round. For tires he was running 255/40/18 PS2s with a mild drop. As you can see they fit fine.

 

DaveB, I'm curious to know what tire size did you ended up going with as I'm in a similar situation as you.

I just bought some 18x8 rims and have to decide whether to go with 235/45 or 245/45 tires on my unlowered G35x. I'm leaning toward 245 at this point but I'm wondering how the steering feel will be effected going from a 215 OEM tire to a 245.

Thanks.